Structure for chair backrest

ABSTRACT

A structure for chair backrest is disclosed. The chair includes a first support frame, a second support frame coupled to the first support frame, a seat section arranged between the first support frame and the second support frame. The first support frame includes a backrest mounted thereon. The first support frame includes a lower frame section and an upper frame section. The lower frame section and the upper frame section include, mounted therebetween, a supine inclination assembly that upon receiving a force acting thereon takes a movement for achieving an predetermined angle of supine inclination. In this way, easy adjustment of the angular position of the backrest may be achieved for comfortableness of the user, and excessive inclination that causes potential risk can be avoided so as to improve the utilization of the backrest of the chair.

(a) TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to a structure for chair backrest, and more particularly to a chair backrest structure that allows for supine inclination of the backrest of a foldable chair thereby improving the utilization of the chair.

(b) DESCRIPTION OF THE PRIOR ART

As shown in FIG. 1, a foldable chair 1 comprises a first support frame 11, a second support frame 12 that intersects and is coupled to the first support frame 11, a seat section 13 mounted between the first support frame 11 and the second support frame 12, and a coupling member 14 connecting the first support frame 11 and the second support frame 12 to each other.

As shown in FIG. 1, the first support frame 11 and the second support frame 12 are connected to each other by means of the coupling member 14. The first support frame 11 is provided, on an upper end thereof, with a backrest 15 to receive the back of a user to rest thereon. The seat section 13 is mounted to a seat frame 131 mounted between the first support frame 11 and the second support frame 12. The seat section 13 may receive a user to sit thereon. When the user sits on the seat section 13, the user's back may incline backwards to lean against the backrest 15 of the first support frame 11. In this way, the hips of the user are supported on the seat section 13 and the back of the user is supported by the backrest 15. In this way, the user may gain comfortableness of sitting.

As shown in FIG. 1, the backrest 15 of the conventional foldable chair 1 is mounted on the first support frame 11. The first support frame 11 is a frame member that is expanded and retained at a fixed angular position. Thus, the support that the backrest 15 provides to the back of the user is at a fixed angular position (which is an angular position of backward inclination). When the user attempts to change the supporting angle of the back (meaning the angle between the back and the hips of user sitting on the chair), the user must move or shift the hips frontward or backward on the seat section 13 in order to achieve a desired a supporting angle for the back. This way of changing the position of the hips on the seat section 13 may be improper and may cause hurt of the waist of the user.

Thus, it is now a challenge for the chair manufacturing industry to provide a structure for chair backrest that helps overcome the deficiency of the backrest of the conventional foldable chair.

SUMMARY OF THE INVENTION

The primary object of the present invention is to provide a structure for chair backrest, which helps overcome the deficiency of the backrest of the conventional foldable chair that possesses no operation for supine inclination to meet the needs of a user.

In this respect, a major technical solution presented in claim 1 of the present invention is to provide a chair backrest structure, wherein the chair comprises a first support frame, a second support frame coupled to the first support frame, a seat section arranged between the first support frame and the second support frame, the first support frame comprising a backrest mounted thereon, wherein the first support frame comprises a lower frame section and an upper frame section, the lower frame section and the upper frame section comprising, mounted therebetween, a supine inclination assembly that upon receiving a force acting thereon takes a movement for achieving an predetermined angle of supine inclination.

The efficacy that the major technical solution of claim 1 of the present invention may achieve is that easy adjustment of an angular position of a backrest may be achieved for comfortableness of a user, and excessive inclination that causes potential risk can be avoided so as to improve the utilization of the backrest of a chair.

The foregoing objectives and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts.

Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a conventional chair.

FIG. 2 is a side elevational view showing a chair according to the present invention.

FIG. 2A is an enlarged view of a portion of FIG. 2.

FIG. 3 is an exploded view showing a supine inclination assembly according to the present invention.

FIG. 4 is a perspective view showing the supine inclination assembly according to the present invention.

FIG. 5 is a perspective view showing the supine inclination assembly according to the present invention from a different perspective.

FIGS. 6 and 7 are schematic views showing an operation of the supine inclination assembly according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following descriptions are exemplary embodiments only, and are not intended to limit the scope, applicability or configuration of the invention in any way. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. Various changes to the described embodiments may be made in the function and arrangement of the elements described without departing from the scope of the invention as set forth in the appended claims.

Firstly, referring to FIGS. 2 and 2A, the present invention provides a backrest structure of a chair. The chair 2 comprises a first support frame 3, a second support frame 4 that is coupled to the first support frame 3, and a seat section 5 arranged between the first support frame 3 and the second support frame 4.

As shown in FIGS. 2 and 2A, the first support frame 3 comprises a lower frame section 31 and an upper frame section 32. The lower frame section 31 and the upper frame section 32 comprise a supine inclination assembly 6 mounted therebetween. The upper frame section 32 is provided with a backrest 7 on which the back of a user may rest. The lower frame section 31 is provided, in an upper end portion thereof, with a through aperture 311. The lower frame section 31 has lower ends to which casters W are mounted.

As shown in FIGS. 2 and 2A, the second support frame 4 is arranged outside the first support frame 3. The second support frame 4 and the first support frame 3 are coupled to each other through a coupling member 8. The second support frame 4 has upper ends to which armrests 41 are mounted. The second support frame 4 has lower ends to which casters W are mounted.

As shown in FIGS. 2 and 2A, the seat section 5 is arranged between the first support frame 3 and the second support frame 4. The seat section 5 comprises a cushion 51 and a seat frame 52. The seat section 5 is coupled, through the seat frame 52, to the first support frame 3 and the second support frame 4.

As shown in FIGS. 3, 4, and 5, the supine inclination assembly 6 comprises an upper insertion piece 61, a lower insertion piece 62, and a return spring 63. The upper insertion piece 61 comprises an upper insertion section 611. The upper insertion piece 61 is provided, on an end thereof opposite to the upper insertion section 611, with an upper connection section 612. The upper connection section 612 comprises an upper accommodation section 613 formed therein. The upper insertion piece 61 comprises an upper fitting section 614 formed therein and extending in a direction from the upper connection section 612 toward the upper insertion section 611. Further, the upper fitting section 614 is provided, at one side of a lower end thereof, with a constraint recess 615. The upper accommodation section 613 comprises an upper through hole 616 formed therein and extending through the upper insertion piece 61. The lower insertion piece 62 comprises a lower insertion section 621. The lower insertion section 621 comprises a locking hole 6211 formed therein. The lower insertion piece 62 is provided, on an end thereof opposite to the lower insertion section 621, with a lower connection section 622. The lower connection section 622 comprises a lower accommodation section 623 formed therein. The lower insertion piece 62 comprises a lower fitting section 624 formed therein and extending in a direction from the lower connection section 622 toward the lower insertion section 621. The lower insertion piece 62 comprises a constraint peg 625 formed thereon and projecting in a direction opposite to the lower insertion section 621. The lower accommodation section 623 comprises a lower through hole 626 formed therein and extending through the lower insertion piece 62. The upper connection section 612 and the lower connection section 622 are opposite to each other and the constraint peg 625 and the constraint recess 615 correspond to each other. The constraint peg 625 has an outside diameter smaller than the constraint recess 615 and the constraint peg 625 is received in the constraint recess 615. The return spring 63 is arranged between the upper accommodation section 613 and the lower accommodation section 623 and the return spring 63 has an end fit into and mounted in the upper fitting section 614 and an opposite end fit into and mounted in the lower fitting section 624.

As shown in FIGS. 2 and 2A, 3, 4, 5, 6, and 7, to assemble the supine inclination assembly 6, the upper accommodation section 613 of the upper insertion piece 61 and the lower accommodation section 623 and the lower insertion piece 62 are set to mate each other and closed together such that the return spring 63 is received and accommodated between the upper accommodation section 613 and the lower accommodation section 623 with one end of the return spring 63 fit into and mounted in the upper fitting section 614 and an opposite end fit into and mounted in the lower fitting section 624, and meanwhile, the constraint peg 625 is set and received in the constraint recess 615. A fastening element S (a bolt being taken as an example in the present invention) is received through the upper through hole 616 of the upper insertion piece 61 and the lower through hole 626 of the lower insertion piece 62 and tightened so as to assemble the upper insertion piece 61 and the lower insertion piece 62 together to form the supine inclination assembly 6. With the springy effect of the return spring 63, the supine inclination assembly 6 allows the upper insertion piece 61 to take a rotational movement of a predetermined angle for supine inclination with respect to the lower insertion piece 62. The supine inclination assembly 6 provides a constraint for the maximum supine inclination angle by having the constraint peg 625 constrained in the constraint recess 615. More specifically, when the constraint peg 625 abuts an inside surface of the constraint recess 615, the supine inclination angle of the upper insertion piece 61 with respect to the lower insertion piece 62 achieved through the rotational movement is limited and the movement is stopped thereby preventing an excessive angle supine inclination of the upper insertion piece 61 with respect to the lower insertion piece 62, which might lead to unexpected risk.

As shown in FIGS. 2 and 2A, 6, and 7, the upper insertion section 611 of the upper insertion piece 61 of the supine inclination assembly 6 is inserted into a lower end of the upper frame section 32 of the first support frame 3; and the lower insertion section 621 of the lower insertion piece 62 is inserted into an upper end of the lower frame section 31 of the first support frame 3. A fastening element S1 is screwed into the through aperture 311 of the lower frame section 31 and the locking hole 6211 of the lower insertion section 621 of the lower insertion piece 62 to fix the lower insertion piece 62 to the lower frame section 31. In this way, the first support frame 3 forms a complete support frame. When it needs to change a supporting angle for the back of the user, the user only needs to apply a force, through the back, to the backrest so that through the operation of the return spring 63, the supine inclination assembly 6 allows the upper insertion piece 61 to take a desired angle of supine inclination with respect to the lower insertion piece 62, while the supine inclination assembly 6 may limit the maximum angle of supine inclination by having the constraint peg 625 fit into the constraint recess 615. In this way, easy adjustment of the angular position of the backrest 7 may be achieved for comfortableness of the user, and on the other hand, the utilization of the backrest 7 of the chair 2 can be improved.

The efficacy of the present invention is that the first support frame 3 comprises a lower frame section 31 and an upper frame section 32 and a supine inclination assembly 6 is coupled between the lower frame section 31 and the upper frame section 32 so that through an operation of a return spring 63, the supine inclination assembly 6 allows the upper insertion piece 61 to take a predetermined angle of supine inclination, as desired by a user, with respect to the lower insertion piece 62. In this way, a user may gain comfortable support to the back without changing or shifting the location of the hips on the seat section. Further, the supine inclination assembly 6 comprises a constraint peg 625, which when fit into a constraint recess 615, sets a limit to a maximum angle of supine inclination. In this way, easy adjustment of the angular position of the backrest 7 may be achieved for comfortableness of the user, and excessive inclination that causes potential risk can be avoided so as to improve the utilization of the backrest 7 of the chair.

It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above.

While certain novel features of this invention have been shown and described and are pointed out in the annexed claim, it is not intended to be limited to the details above, since it will be understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing in any way from the claims of the present invention. 

I claim:
 1. A chair backrest structure, wherein the chair comprises a first support frame, a second support frame coupled to the first support frame, a seat section arranged between the first support frame and the second support frame, the first support frame comprising a backrest mounted thereon, wherein the first support frame comprises a lower frame section and an upper frame section, the lower frame section and the upper frame section comprising, mounted therebetween, a supine inclination assembly that upon receiving a force acting thereon takes a movement for achieving an predetermined angle of supine inclination.
 2. The chair backrest structure according to claim 1, wherein the backrest is mounted to the upper frame section.
 3. The chair backrest structure according to claim 1, wherein the supine inclination assembly comprises an upper insertion piece, a lower insertion piece, and a return spring; the upper insertion piece comprises an upper insertion section, the upper insertion piece being provided, on an end thereof opposite to the upper insertion section, with an upper connection section, the upper connection section comprising an upper accommodation section formed therein, the upper insertion piece comprising an upper fitting section formed therein and extending in a direction from the upper connection section toward the upper insertion section, the upper fitting section being provided, at one side of a lower end thereof, with a constraint recess; the upper accommodation section comprises an upper through hole formed therein and extending through the upper insertion piece; the lower insertion piece comprises a lower insertion section, the lower insertion section comprising a locking hole formed therein, the lower insertion piece being provided, on an end thereof opposite to the lower insertion section, with a lower connection section, the lower connection section comprising a lower accommodation section formed therein, the lower insertion piece comprising a lower fitting section formed therein and extending in a direction from the lower connection section toward the lower insertion section, the lower insertion piece comprising a constraint peg formed thereon and projecting in a direction opposite to the lower insertion section; the lower accommodation section comprises a lower through hole formed therein and extending through the lower insertion piece; the return spring is arranged between the upper accommodation section and the lower accommodation section and the return spring has an end fit into and mounted in the upper fitting section and an opposite end fit into and mounted in the lower fitting section; and the upper insertion section of the upper insertion piece is inserted into a lower end of the upper frame section of the first support frame and the lower insertion section of the lower insertion piece is inserted into an upper end of the lower frame section of the first support frame.
 4. The chair backrest structure according to claim 3, wherein the lower insertion section of the lower insertion piece is provided with a locking hole formed therein, the lower frame section comprising a through aperture formed therein, a fastening element being screwed to the through aperture and the locking hole to fix the lower insertion piece to the lower frame section.
 5. The chair backrest structure according to claim 3, wherein the upper connection section and the lower connection section are opposite to each other and the constraint peg and the constraint recess correspond to each other, the constraint peg having an outside diameter smaller than the constraint recess, the constraint peg being received in the constraint recess.
 6. The chair backrest structure according to claim 3, wherein the constraint peg is engageable with an inside surface of the constraint recess to stop a movement of the upper insertion piece to take an angle of supine inclination with respect to the lower insertion piece so as to limit a maximum angle of supine inclination of the backrest.
 7. The chair backrest structure according to claim 1, wherein the first support frame and the second support frame are coupled to each other with a coupling member; and lower ends of the first support frame and the second support frame are provided with casters, the second support frame having an upper end to which armrests are mounted.
 8. The chair backrest structure according to claim 1, wherein the seat section comprises a cushion and a seat frame, the seat section being coupled through the seat frame between the first support frame and the second support frame. 